Constraints on Primordial Gravitational Waves Using Planck , WMAP, and New BICEP2/ Keck Observations through the 2015 Season

Abstract

We present results from an analysis of all data taken by the BICEP2/Keck CMB polarization experiments up to and including the 2015 observing season. This includes the first Keck Array observations at 220 GHz and additional observations at 95 & 150 GHz. The Q/U maps reach depths of 5.2, 2.9 and 26 µKcmb arcmin at 95, 150 and 220 GHz respectively over an effective area of ≈ 400 square degrees. The 220 GHz maps achieve a signal-to-noise on polarized dust emission approximately equal to that of Planck at 353 GHz. We take auto-and cross-spectra between these maps and publicly available WMAP and Planck maps at frequencies from 23 to 353 GHz. We evaluate the joint likelihood of the spectra versus a multicomponent model of lensed-ΛCDM+r+dust+synchrotron+noise. The foreground model has seven parameters, and we impose priors on some of these using external information from Planck and WMAP derived from larger regions of sky. The model is shown to be an adequate description of the data at the current noise levels. The likelihood analysis yields the constraint r0.05 < 0.07 at 95% confidence, which tightens to r0.05 < 0.06 in conjunction with Planck temperature measurements and other data. The lensing signal is detected at 8.8σ significance. Running maximum likelihood search on simulations we obtain unbiased results and find that σ(r) = 0.020. These are the strongest constraints to date on primordial gravitational waves.

Constant-roll in the Palatini-R2 models

“…It is worth mentioning that all the values of α, presented in the above table, together with the values of β and λ, produce a power spectrum P s ∼ 10 −9 , close to its observed value. The results are well within the allowed region of n s and r from the Planck2018 collaboration [14] (see also [15]), which is n s = (0.9607, 0.9691), 1σ region (0.9565, 0.9733), 2σ region , r < 0.064. (4.8)…”

Axion dark matter from Higgs inflation with an intermediate H*

“…As a result, the Higgs potential in the Einstein frame develops a plateau suitable for slow-roll inflation. The predictions of the model are in perfect agreement with the current observational data from the Planck mission [20][21][22], and the model has also been invoked in unified frameworks like the SMASH model [55]. However, the original Higgs inflation model [56] predicts a scale of inflation H * 10 13 GeV which, due to the bound on CDM isocurvature perturbations, does not allow the axion to constitute all of the observed CDM [23][24][25][26].…”

Initial conditions for plateau inflation: a case study

“…so that in case of large α, the scenario yields negligible primordial gravitation waves. The Planck and BICEP2/Keck Array limits for the aforementioned observables are [7,63] A s = 2.1 × 10 −9 , n s = 0.9625 ± 0.0048 , r < 0.06 , (2.12) measured at the pivot scale k = 0.05 Mpc −1 . In this paper, we will show by studying few example potentials that the slow-roll solution is still an attractor in the presence of the nonminimal kinetic terms, so the results (2.9) and (2.11) are general and practically independent of the initial conditions.…”